Existing direct broadcast satellite systems have difficulty transmitting two programs of high definition television (HDTV) simultaneously in a single channel. For example, the Integrated Services Digital Broadcasting-Satellite (ISDB-S) standard employs an eight phase shift keying (8PSK) based system that requires expanded bandwidth and increased transmission power to accommodate two HDTV programs simultaneously. Standards with conventional quadrature phase shift keying (QPSK) based systems, such as the Digital Satellite System (DSS®) and the Digital Video Broadcast-Satellite (DVB-S) systems, also lack the bandwidth and available transmit power to accommodate two simultaneous HDTV programs.
It would be desirable to broadcast two HDTV programs simultaneously in a single direct broadcast satellite channel while remaining within existing bandwidth and power constraints. This would allow the existing constellation of satellites and home-based antenna systems to remain unmodified while doubling the programming capability of the system.